/* In case your <GL/gl.h> does not advertise EXT_texture_cube_map... */
#ifndef GL_EXT_texture_cube_map
# define GL_NORMAL_MAP_EXT                   0x8511
# define GL_REFLECTION_MAP_EXT               0x8512
# define GL_TEXTURE_CUBE_MAP_EXT             0x8513
# define GL_TEXTURE_BINDING_CUBE_MAP_EXT     0x8514
# define GL_TEXTURE_CUBE_MAP_POSITIVE_X_EXT  0x8515
# define GL_TEXTURE_CUBE_MAP_NEGATIVE_X_EXT  0x8516
# define GL_TEXTURE_CUBE_MAP_POSITIVE_Y_EXT  0x8517
# define GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_EXT  0x8518
# define GL_TEXTURE_CUBE_MAP_POSITIVE_Z_EXT  0x8519
# define GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_EXT  0x851A
# define GL_PROXY_TEXTURE_CUBE_MAP_EXT       0x851B
# define GL_MAX_CUBE_MAP_TEXTURE_SIZE_EXT    0x851C
#endif //GL_EXT_texture_cube_map